Customized Surgical Guides

ABSTRACT

A surgical guide includes a metal guide and a plastic reference formed by additive manufacturing. The metal guide is configured to engage a bone surface of a first body area. The metal guide includes a main plate and an arm. The main plate has an inner surface customized and shaped to the bone surface. The main plate defines mounting guides for securing the main plate to the bone surface and defines a machining guide for drilling or cutting through the bone surface. The arm is formed to the main plate at a proximal end and extends to a distal end. The plastic reference has a reference surface customized and shaped to a surface of a second body area that is physically separated from the first body area.

CROSS-REFERENCE TO RELATED APPLICATIONS

This non-provisional patent application claims priority to U.S.Provisional Application Ser. No. 63/093,825, Entitled “ImprovedCustomized Surgical Guides” by Tarik Kramcha, filed on Oct. 20, 2020,incorporated herein by reference under the benefit of U.S.C. 119(e).

FIELD OF THE INVENTION

The present disclosure relates to the field of surgical tools forguiding the drilling and/or cutting of bone in a human patient. Moreparticularly, the present disclosure improves the accuracy and efficacyof surgical guides.

BACKGROUND

Surgical guides facilitate the transfer of a predetermined surgical planto an operating room. There is a need to have high placement accuracy ofthe surgical guides on the patient anatomy. At the same time, thesurgical guides need to have a rigidity and material strength sufficientto guide surgical drilling and cutting instruments. A key challenge isin providing a surgical guide that possesses both sufficient strengthand rigidity to guide surgical instruments, and the flexibility to beaccurately placed on the patient anatomy through contact with bodysurfaces that provide a reliable reference for alignment.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is an image or drawing depicting an embodiment of a surgicalguide in an unassembled state.

FIG. 2 is an image or drawing depicting an embodiment of a surgicalguide in an assembled state.

FIG. 3 is an image or drawing depicting an embodiment of a surgicalguide being used for a craniomaxillofacial surgery.

FIG. 4 is a flowchart of an embodiment of a method for surgicalplanning, creating surgical guides, and performing a surgery using thesurgical guides.

FIG. 5 is a schematic block diagram of a system for manufacturing asurgical guide.

SUMMARY

In a first aspect of the disclosure, a surgical guide includes a metalguide and a plastic reference. The metal guide is configured to engage abone surface of a first body area and is formed integrally by a firstadditive manufacturing process. The metal guide includes a main plateand an arm. The main plate has an inner surface customized and shaped tothe bone surface. The main plate defines mounting guides foraccommodating bone screws for securing the main plate to the bonesurface and defines one or more drilling and/or cutting guides fordrilling and/or cutting through the bone surface. The arm is formed tothe main plate at a proximal end and extends to a distal end. Theplastic reference is formed by a second additive manufacturing processand has a reference surface customized and shaped to a surface of asecond body area that is physically separated from the first body area.The distal end of the arm is coupled to the plastic reference over thesecond body area. Interengagement of the distal end to the plasticreference and placement to the surface of the second body area providesalignment of the main plate to the bone surface to allow the main plateto be accurately secured to the bone surface. The one or more drillingand/or cutting guides can include a metal-defined slot for guiding abone saw. The one or more drilling and/or cutting guides can includecylindrical guides for guiding a surgical drill.

The use of metal for the arm provides rigidity and precision alignmentof the plastic reference with respect to the main plate. This in turnimproves alignment registration of the main plate with respect to thebone surface. The use of a plastic reference is more compatible withengaging the surface of the second body area, which is generally morecomplex in terms of geometry than the first body area. Also, featuresformed into the plastic reference can be more precisely registered tocomplexly shaped patient anatomy than metal. Finally, the hardness ofplastic features is compatible with referencing patient anatomy such asteeth, circumventing the risk of damage to patient anatomy from contactwith relatively harder metal features.

The first additive manufacturing process can be based on a layer bylayer fusion of metal powder using one or more of a laser or an electronbeam. The second additive manufacturing process can be based uponpolymer powder fusion (e.g., selective laser sintering of nylon powder)or polymer resin curing (e.g., stereolithography or selectiveapplication of radiation to liquid photocurable resin).

In one implementation, the main plate is customized for a facial bone ofa patient. The plastic reference can include recesses for receiving andaligning to upper teeth of the patient.

In other implementations, the surgical guide can be customized fornon-facial regions of the body. For example, the surgical guide can becustomized for orthopedic surgeries.

In a second aspect of the disclosure, a method of manufacturing asurgical guide includes obtaining data to define a surgical guide for apatient, operating a first additive manufacturing (AM) system to form ametal guide which includes a rigidly attached arm, and operating asecond additive manufacturing (AM) system to form a plastic reference.The data includes a geometry of a bone surface of a first body area, ageometry of a main plate of a metal guide to be fitted to the bonesurface, a geometry of a body surface of a second body area, the firstbody area and the second body area are not contiguous, a geometry of aplastic reference to be fitted to the body surface, and a geometry of anarm extending from the main plate to the plastic reference and couplingbetween the coupling arm and the plastic reference.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 is an image or drawing depicting an embodiment of a surgicalguide 2 in an unassembled state. Surgical guide 2 includes a metal guide4 and a plastic reference 6. The metal guide 4 is integrally formed by afirst additive manufacturing (AM) process and the plastic reference 6 isintegrally formed by a second additive manufacturing (AM) process.

The first additive manufacturing process can be based upon a layer bylayer process including a selective melting or sintering of metalpowder. Such a process can have the following steps: (1) A generallyplanar layer of metal powder is deposited on a generally planar surface.(2) An energy beam selectively melts or sinters the layer of metalpowder. The energy beam can be one or more of a laser beam or electronbeam. (3) Steps (1) and (2) can be repeated to additively form the metalguide. Other processes for forming the metal guide 4 are possible.

The second additive manufacturing process can be based upon a layer bylayer process including a selective sintering or melting of plasticpowder layers. Alternatively the second additive manufacturing processcan be based upon a layer by layer process including a selectivepolymerization of a photocurable liquid resin which is sometimesreferred to as stereolithography. Other processes for forming theplastic reference 6 are possible such as by selective dispensing ofpolymers.

The metal guide 4 includes a main plate 8 and an arm 10. In theillustrated embodiment, the main plate 8 includes drilling guides 12, acutting guide 14 and one or more mounting guides 15. In the illustratedembodiment, the drilling guides 12 are elongated cylindrical structuresthat define cylindrical openings 16. The cutting guide 14 is illustratedas a guide slot 14. The mounting guides 15 define circular openings inthe main plate 8. The arm 10 has a proximal end 20 where it is attachedto an “outer” surface 22 of the main plate 8. The arm 10 also has adistal end 24 defining an opening 26. The main plate has an opposinginner surface 23 on an opposite side of the main plate 8 relative to theouter surface 22.

The plastic reference 6 has a reference surface 28. In the illustratedembodiment, the reference surface 28 defines a plurality of recesses 30.Also in the illustrated embodiment the plastic reference 6 also includesan upstanding datum 32.

In contrast to FIG. 1, FIG. 2 illustrates the surgical guide 2 in anassembled state. Assembly of surgical guide 2 takes place when thedistal end 24 of arm 10 is interengaged and coupled to the plasticreference 6. The interengaged assembly of the distal end 24 of arm 10 tothe reference 6 will be referred to as an assembled interface 34. In theillustrated embodiment, the assembled interface 34 is formed when theupstanding datum 32 of the reference 6 is received into the opening 26of the distal end 24 of arm 10. However, it is to be understood that theassembled interface 34 could be formed between an upstanding datum ofthe distal end 24 being received into an opening formed into thereference 6. Other methods of coupling with different features are alsopossible to form the assembled interface 34 when the distal end 24 iscoupled to the plastic reference 6.

Coupling the distal end 24 of arm 10 to reference 6 provides a rigid andaccurate location of the main plate 8 with respect to the referencesurface 28. In the illustrated embodiment, the plurality of recesses 30are also accurately located with respect to the main plate 8.

FIG. 3 is an illustration of the surgical guide 2 in use with a model ofa patient skull 36. In the illustrated embodiment, the recesses 30defined by reference surface 28 have received upper teeth of the patientskull 36. This in turn mechanically aligns the main plate 8, includingthe cutting guide 14 and drilling guides 12, to a bone surface 38 of theskull 36. This alignment allows the main plate 8 to be accuratelyaligned and then mounted to the bone surface 38 using the mountingguides 15.

In the illustrated embodiment, the surgical guide 2 is positioned over afirst body area 40 and a second body area 42. The first 40 and second 42body areas are non-contiguous. The first body area 40 includes the bonesurface 38. The second body area 42 includes a body surface 44. In theillustrated embodiment, the body surface 44 includes the upper teeth.Further embodiments of the present invention position over a differentsecond body area or body surface that may advantageous for a reference.

The main plate 8 is mounted within the first body area 40. The innersurface 23 of the main plate 8 is mounted against the bone surface 38.The reference surface 28 of the plastic reference 6 is mounted to thesecond body area 42. In the illustrated embodiment, the referencesurface 28 defines recesses 30 that receive the teeth. The arm 10extends between the non-contiguous areas 40 and 42.

FIG. 4 is a flowchart depicting a method 100 of surgical planning(102-106), creating surgical guides (108-110) and performing a surgeryfacilitated by the surgical guide 2 (112-118). Some of the steps ofmethod 100 are performed in an automated way by computer and some areperformed manually. Steps 102-110 of method 100 can be referred to asmethod 101 which is a method of manufacturing the surgical guide 2.

According to 102, patient data or information is obtained. Obtainingthis data may include imaging of a patient's body areas with an imagingmachine 126 (FIG. 5). According to 104, three-dimensional (3D) models ofpatient anatomy are generated based upon the data obtained from 102.

According to 106, a surgical plan is determined. This surgical plandefines cutting and/or drilling geometry to be performed on the patient.According to 108, the multi-material (metal and plastic) surgical guide2 is defined based upon the surgical plan and the 3D models of patientanatomy.

In performing steps 104, 106, and 108, certain data can be generatedincluding the following: data defining a geometry of the bone surface 38of the first body area 40; data defining a geometry of the main plate 8based upon the geometry of the bone surface 38 and the surgical plan;data defining a geometry of the body surface 44 of the second body area42; data defining a geometry of the plastic reference 6 and thereference surface 28; data defining a geometry of the arm 10; datadefining the interface 34 between the distal end 24 of arm 10 and theplastic reference 6.

According to 110, additive manufacturing (AM) machines are operated tofabricate the surgical guide 2. This includes operating a first additivemanufacturing (AM) machine to form the metal guide 4 and a secondadditive manufacturing (AM) machine to form the plastic reference 6.

According to 112, the plastic reference 6 is aligned to and engaged withthe body surface 44. According to 114, the distal end 24 of arm 10 ofthe metal guide 4 is coupled to the plastic reference 6 to forminterface 34.

According to 116, the main plate 8 is aligned to and placed upon thefirst body area 40. The engagement between the plastic reference and thebody surface 44 assures accurate alignment of the main plate 8 to thefirst body area 40. As part of step 116, bone screws are used to mountthe main plate to the first body area 40.

According to 118, the main plate 8 is used to guide cutting and/ordrilling on the first body area 40. In an illustrated embodiment, theguide slot 14 is used to guide a cutting blade operation upon the bonesurface 38. The drilling guides 12 are used to guide a drill bit for aprecision drilling operating into the bone surface 38.

Other methods are possible. For example, step 114 can be performedbetween steps 110 and 112 as part of a manufacturing process for thesurgical guide 2.

FIG. 5 is a schematic block diagram depicting a system 120 forperforming steps 102-110 of the method 100 or 101 for manufacturing thesurgical guide 2. A controller 122 is electrically or wirelessly linkedto a user interface 124, an imaging machine 126, a first AM machine 128,and a second AM machine 130.

Controller 122 includes a processor 132 coupled to an informationstorage device 134. Information storage device 134 includes non-volatileor non-transient storage media portions that store softwareinstructions. When executed by the processor 132, the instructions canoperate and receive information from the user interface device 124, theimaging machine 126, the AM machine 1, and the AM machine 2 and canperform steps 102-110 of method 100 or method 101 of FIG. 4. Controller122 can be a single physical controller or it can be a distribution ofnetworked or otherwise linked controllers. In some embodiments, portionsof controller 122 can be physically integrated with one or more of theuser interface device 124, the imaging machine 126, first AM machine128, and second AM machine 130.

User interface device 124 can include one or more of a mobile device, asmartphone, a laptop computer, a notebook computer, a desktop computer,a computer terminal, and various other computing devices. Through theuser interface device 124, a user can initiate method 101.

The imaging machine 126 can include one or more of a computerizedtomography (CT) scan machine, an X-ray machine, a magnetic resonanceimaging (MRI) machine, a positron emission tomography (PET) machine, andother methods of imaging. The imaging machine 126 can perform step 102of method 100 or 101.

The first AM machine 128 and second AM machine 130 are used to performstep 110 of FIG. 4. The first AM machine 128 is operated to form themetal guide 4. The second AM machine 130 is operated to form the plasticreference 6. In an alternative embodiment, the first AM machine 128forms a very high modulus of elasticity and/or filled plastic guide 6.

The specific embodiments and applications thereof described above arefor illustrative purposes only and do not preclude modifications andvariations encompassed by the scope of the following claims.

What is claimed:
 1. A surgical guide comprising: a metal guideconfigured to engage a bone surface of a first body area, the metalguide formed integrally by a first additive manufacturing process andincluding: a main plate having an inner surface customized and shaped tothe bone surface, the main plate defining mounting guides for securingthe main plate to the bone surface and defining a drilling and/orcutting guide for drilling and/or cutting through the bone surface; andan arm that is formed to the main plate at a proximal end and extends toa distal end; and a plastic reference formed integrally by a secondadditive manufacturing process and having a reference surface customizedand shaped to a surface of a second body area that is physicallyseparated from the first body area; the distal end of the arm isconfigured to be coupled to the plastic reference, interengagement ofthe distal end to the plastic reference and placement of the plasticreference on the surface of the second body area provides alignment ofthe main plate to the bone surface to allow the main plate to beaccurately aligned and secured to the bone surface.
 2. The surgicalguide of claim 1 wherein the first additive manufacturing processincludes a layer by layer fusion of metal powder using one more of alaser and an electron beam.
 3. The surgical guide of claim 1 wherein themachining guide includes a slot for guiding a bone saw and/or cylindersfor guiding a surgical drill.
 4. The surgical guide of claim 1 whereinthe mounting guides include cylindrical openings for accommodating bonescrews.
 5. The surgical guide of claim 1 wherein the inner surface ofthe main plate is customized for a craniomaxillofacial bone.
 6. Thesurgical guide of claim 5 wherein the reference surface includes aplurality of recesses that are customized to a patient's teeth.
 7. Thesurgical guide of claim 1 wherein the main plate has an outer surface inopposing relation to the inner surface, the metal arm extends away fromthe outer surface and then to the second body area.
 8. The surgicalguide of claim 1 wherein the second additive manufacturing process isone or more of selectively laser sintering of polymer powder andstereolithographic imaging of a photocurable polymer resin liquid. 9.The surgical guide of claim 1 wherein the reference surface includes aplurality of recesses that are customized to a patient's teeth.
 10. Amethod of manufacturing a surgical guide comprising: obtaining data todefine the surgical guide for a patient including: a geometry of a bonesurface of a first body area; a geometry of a main plate of a metalguide to be fitted to the bone surface; a geometry of a body surface ofa second body area, the first body area and the second body area are notcontiguous; a geometry of a plastic reference to be fitted to the bodysurface; and a geometry of an arm extending from the main plate to theplastic reference and coupling between the coupling arm and the plasticreference, the geometry of the arm partially based upon a relativeposition of the first body area with respect to the second body area;operating a first additive manufacturing system to print the metal guidewhich includes the arm rigidly integrated with the main plate; andoperating a second additive manufacturing system to print the plasticreference.
 11. The method of claim 10 wherein the method furtherincludes coupling the arm to the plastic reference includinginterengaging a distal end of the arm to the plastic reference.
 12. Themethod of claim 10 wherein the main plate includes circular openings forguiding bone screws for attaching the main plate to the bone surface.13. The method of claim 10 wherein the main plate includes a slot forguiding a bone saw and/or cylinders for guiding a surgical drill. 14.The method of claim 10 wherein operating the first additivemanufacturing system includes fusing layers of metal powder with a laseror electron beam.
 15. The method of claim 10 wherein the body surfaceincludes teeth, the plastic reference has a reference surface withrecesses for fitting to and aligning to the teeth.
 16. A method ofperforming surgery comprising: obtaining data to facilitate the surgeryfor a patient including: a geometry of a bone surface of a first bodyarea; a geometry of a main plate of a metal guide to be fitted to thebone surface; a geometry of a body surface of a second body area, thefirst body area and the second body area are not contiguous; a geometryof a plastic reference to be fitted to the body surface; and a geometryof an arm extending from the main plate to the plastic reference andcoupling between the coupling arm and the plastic reference; operating afirst additive manufacturing system to print the metal guide whichincludes the arm integrated with the main plate; operating a secondadditive manufacturing system to print the plastic reference; engagingthe plastic reference with the body surface; coupling the arm to theplastic reference; attaching the main plate to the bone surface; andperforming the surgery using the main plate as a guide.
 17. The methodof claim 16 wherein the main plate includes one or more mounting guidesfor guiding one or more bone screws, and wherein attaching the mainplate to the bone surface includes locating the one or more bone screwswith the one or more mounting guides.
 18. The method of claim 16 whereinthe main plate includes a slot for guiding a bone saw and performing thesurgery includes guiding a bone saw with the slot and forming a cut inthe bone surface.
 19. The method of claim 16 wherein the main plateincludes one or more cylindrical openings and performing the surgeryincludes guiding the a drill with the one or more cylindrical openingsto perform one or more precision drilling operations into the bonesurface.
 20. The method of claim 16 wherein operating the first additivemanufacturing system includes fusing layers of metal powder with a laseror electron beam.
 21. The method of claim 16 wherein coupling the arm tothe plastic reference includes interengaging a distal end of the arm tothe plastic reference at a location over the second body area.
 22. Themethod of claim 16 wherein the body surface includes teeth, the plasticreference has a reference surface with recesses, engaging the plasticsurface with the body surface includes fitting the recesses over theteeth.
 23. The method of claim 16 wherein the bone surface includes asurface of a craniomaxillofacial bone.